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HelpOrder Code LALBS Lysosomal Acid Lipase, Blood Spot
Useful For
Evaluation of patients with a clinical presentation suggestive of lysosomal acid lipase deficiency using blood spot specimens
This test is not useful to determine carrier status for cholesteryl ester storage disease or Wolman disease.
Reporting Name
Lysosomal Acid Lipase, BSSpecimen Type
Whole bloodNecessary Information
Provide a reason for testing with each specimen.
Specimen Required
Supplies: Card-Blood Spot Collection (Filter Paper) (T493)
Collection Container/Tube:
Preferred: Blood spot collection card
Acceptable: PerkinElmer 226 filter paper, Munktell TFN, and Whatman Protein Saver 903 Paper
Specimen Volume: 2 Blood spots
Collection Instructions:
1. Completely fill at least 2 circles on the filter paper card (approximately 100 microliters blood per circle).
2. An alternative blood collection option for a patient older than 1 year is a fingerstick. For detailed instructions, see How to Collect Dried Blood Spot Samples.
3. Let blood dry on the filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.
4. Do not expose specimen to heat or direct sunlight.
5. Do not stack wet specimens.
6. Keep specimen dry.
Additional Information:
1. For collection instructions, see Blood Spot Collection Instructions.
2. For collection instructions in Spanish, see Blood Spot Collection Card-Spanish Instructions (T777).
3. For collection instructions in Chinese, see Blood Spot Collection Card-Chinese Instructions (T800).
Specimen Minimum Volume
1 Blood spot
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Refrigerated (preferred) | 28 days | FILTER PAPER |
| Frozen | 90 days | FILTER PAPER | |
| Ambient | 7 days | FILTER PAPER |
Reject Due To
| Shows serum rings Multiple layers |
Reject |
Reference Values
≥21.0 nmol/h/mL
Method Description
A 3-mm (one-eighth inch) disk is punched out of the dried blood spot into a microcentrifuge tube and water is added as a preincubation extraction that takes place on an orbital shaker. Extraction liquid is combined with either water (total activity well) or Lalistat (inhibited well) in a black 96-well plate. The plate is incubated. The substrate is then added to the same plate. After the incubation period, calibrators are prepared and analyzed on every plate to calculate enzyme activity results based on fluorescence units in patient wells vs calibrators. The calibration is derived from 4-methylumbelliferone (4-MU) that is serially diluted manually in the plate, with the highest calibrator being equivalent to an enzyme activity of 672.0 nmol/hour/mL blood. The plate is then ready to be read using the spectrofluorometer. Enzyme activity is calculated by subtracting the inhibited activity from total activity.(Hamilton J, Jones I, Srivastava R, Galloway P. A new method for the measurement of lysosomal acid lipase in dried blood spots using the inhibitor Lalistat 2. Clin Chim Acta. 2012;413(15-16):1207-1210; Cowan T, Pasquali M: Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1139-1158)
Day(s) Performed
Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82657
Method Name
Fluorometric Enzyme Assay
Special Instructions
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Biochemical Genetics Patient Information (T602)
3. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
Genetics Test Information
This test provides diagnostic testing for patients with clinical signs and symptoms suspicious for lysosomal acid lipase deficiency (LALD).
LALD is expressed phenotypically as infantile-onset Wolman disease or later-onset cholesterol ester storage disease.